A correlative study of the function and pharmacology of frog retinal ganglion cells is proposed. Extracellular ganglion cell responses to a spatiotemporal white noise stimulus will be used to determine detailed receptive field properties. This technique provides an objective, quantitative basis for defining ganglion cell function. The analysis has been used extensively by the PI in frog and cat receptive field analysis. We will continue to use traditional stimuli however in order that we can compare results with previous work by other investigators. Using nonlinear analysis, both spatial and temporal features of ganglion cell receptive fields will be determined. We propose to use pharmacological probes such as the administration of Gamma-aminobutyric acid (GABA) and glycine antagonists to augment the study of receptive field properties. Additional studies will focus on ganglion cell temporal receptive field properties in retinas previously depleted of dopamine with the neurotoxin Delta-hydroxydopamine (6HDA).